Communication control apparatus, communication control method, radio communication system and terminal apparatus

ABSTRACT

[Object] To utilize the extension band in the band-filling efficiently. 
     [Solution] There is provided a communication control apparatus including: a communication control unit that controls radio communication performed by terminal apparatuses on a component carrier having a basic bandwidth, and sets at least one extension band to be added to the component carrier to at least a part of an excess frequency band. The terminal apparatuses include a first group of terminal apparatuses that support radio communication on the extension band, and a second group of terminal apparatuses that do not support the radio communication on the extension band. The communication control unit transmits resource assignment information that is not changed depending on whether or not the extension band is set, for the second group of terminal apparatuses.

TECHNICAL FIELD

The present disclosure relates to a communication control apparatus, acommunication control method, a radio communication system and aterminal apparatus.

BACKGROUND ART

In long term evolution (LTE) that is a cellular communication schemestandardized in the third generation partnership project (3GPP), as abandwidth used for radio communication, 6 alternatives of 1.4 MHz, 3MHz, 5 MHz, 10 MHz, 15 MHz and 20 MHz are defined (see, for example,Non-Patent Literature 1). In LTE-advanced (LTE-A) obtained by developingthe LTE, technology called carrier aggregation is further introduced,which allows a plurality of component carriers each having any bandwidthdescribed above to be integrally used. For example, when the twocomponent carriers each having a bandwidth of 20 MHz are simultaneouslyused, it is possible to form a radio channel of 40 MHz in total.

However, frequency bands assigned to communication providers in eachcountry are not always adapted to the bandwidths defined in the LTE(hereinafter, a term of the LTE also includes the LTE-A). Therefore,when the communication providers operate an LTE system, an excessfrequency band may remain as it is without being used. Then, a conceptcalled band-filling has been proposed, in which an extension band is setto the excess frequency band adjacent to the component carrier, and theextension band is also used for radio communication, in order to improveutilization efficiency of frequency resources (see, for example,Non-Patent Literature 2).

CITATION LIST Non-Patent Literature

-   Non-Patent Literature 1: 3GPP, “3GPP TS 36.104 V11.4.0”, Mar. 22,    2013-   Non-Patent Literature 2: AT&T, “NCT and Band Filling”, R1-130665,    3GPP TSG RAN WG1 Meeting #728, Jan. 28-Feb. 1, 2013

SUMMARY OF INVENTION Technical Problem

However, if the communication providers can freely set the extensionband to the excess frequency band, various problems such as complicationof implementation, an increase in overhead, deterioration incommunication quality and a loss of backward compatibility may becaused.

Therefore, it is desirable to provide a system capable of utilizing theextension band efficiently by solving or reducing at least one of theproblems assumed related to the band-filling.

Solution to Problem

According to the present disclosure, there is provided a communicationcontrol apparatus including: a communication control unit that controlsradio communication performed by terminal apparatuses on a componentcarrier having a basic bandwidth, and sets at least one extension bandto be added to the component carrier to at least a part of an excessfrequency band. The terminal apparatuses include a first group ofterminal apparatuses that support radio communication on the extensionband, and a second group of terminal apparatuses that do not support theradio communication on the extension band. The communication controlunit transmits resource assignment information that is not changeddepending on whether or not the extension band is set, for the secondgroup of terminal apparatuses.

According to the present disclosure, there is provided a communicationcontrol method including: controlling radio communication performed byterminal apparatuses on a component carrier having a basic bandwidth;setting at least one extension band to be added to the component carrierto at least a part of an excess frequency band; including a first groupof terminal apparatuses that support radio communication on theextension band, and a second group of terminal apparatuses that do notsupport the radio communication on the extension band, in the terminalapparatuses; and transmitting resource assignment information that isnot changed depending on whether or not the extension band is set, forthe second group of terminal apparatuses.

According to the present disclosure, there is provided a radiocommunication system including a communication control apparatus and aplurality of terminal apparatuses that execute radio communication. Thecommunication control apparatus includes a communication control unitthat sets a component carrier having a basic bandwidth and sets at leastone extension band to be added to the component carrier to at least apart of an excess frequency band. The plurality of terminal apparatusesinclude a first group of terminal apparatuses that support radiocommunication on the extension band, and a second group of terminalapparatuses that do not support the radio communication on the extensionband. The communication control unit of the communication controlapparatus transmits resource assignment information that is not changeddepending on whether or not the extension band is set, for the secondgroup of terminal apparatuses.

According to the present disclosure, there is provided a terminalapparatus including: a radio communication unit that communicates with acommunication control apparatus controlling radio communicationperformed on a component carrier having a basic bandwidth, thecommunication control apparatus setting at least one extension band tobe added to the component carrier to at least a part of an excessfrequency band; and a control unit that allows the radio communicationunit to execute the radio communication according to resource assignmentinformation received from the communication control apparatus in aformat different depending on whether or not the extension band is setby the communication control apparatus.

Advantageous Effects of Invention

According to the technology according to the present disclosure, it ispossible to utilize the extension band in the band-filling efficiently.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is an explanatory diagram for explaining an outline of an LTEsystem.

FIG. 2 is an explanatory diagram for explaining an example of aconfiguration of a downlink resource.

FIG. 3 is an explanatory diagram for explaining an example of aconfiguration of an uplink resource.

FIG. 4A is an explanatory diagram for explaining a first example of anarrangement of a component carrier in a frequency domain.

FIG. 4B is an explanatory diagram for explaining a second example of anarrangement of a component carrier in a frequency domain.

FIG. 4C is an explanatory diagram for explaining a third example of anarrangement of a component carrier in a frequency domain.

FIG. 5A is an explanatory diagram illustrating an example of anextension band set on one side.

FIG. 5B is an explanatory diagram for explaining the setting of theextension band in a resource block unit, related to the example of FIG.5A.

FIG. 6A is an explanatory diagram illustrating an example of theextension band symmetrically set on both sides.

FIG. 6B is an explanatory diagram for explaining the setting of theextension band in the resource block unit, related to the example ofFIG. 6A.

FIG. 7A is an explanatory diagram illustrating an example of theextension band asymmetrically set on both sides.

FIG. 7B is an explanatory diagram for explaining the setting of theextension band in the resource block unit, related to the example ofFIG. 7A.

FIG. 8A is an explanatory diagram for explaining an example of anarrangement of a synchronization resource and a broadcast channel inone-side setting.

FIG. 8B is an explanatory diagram for explaining an example of anarrangement of the synchronization resource and the broadcast channel inboth-side symmetric setting.

FIG. 9A is an explanatory diagram for explaining an example of anarrangement of an uplink control channel in the one-side setting.

FIG. 9B is an explanatory diagram for explaining an example of anarrangement of the uplink control channel in the both-side symmetricsetting.

FIG. 10A is an explanatory diagram for explaining a resource blocknumber granted according to an existing method.

FIG. 10B is an explanatory diagram for explaining a first example of anew numbering rule of the resource block number.

FIG. 10C is an explanatory diagram for explaining a second example of anew numbering rule of the resource block number.

FIG. 11 is an explanatory diagram for explaining an example ofband-filling (BF) setting information.

FIG. 12 is an explanatory diagram for explaining a first example of asystem for suppressing noise or interference.

FIG. 13 is an explanatory diagram for explaining a second example of asystem for suppressing noise or interference.

FIG. 14 is a block diagram illustrating an example of a configuration ofa base station according to an embodiment.

FIG. 15A is an explanatory diagram illustrating a first setting exampleof the extension band.

FIG. 15B is an explanatory diagram illustrating a second setting exampleof the extension band.

FIG. 15C is an explanatory diagram illustrating a third setting exampleof the extension band.

FIG. 16 is a block diagram illustrating an example of a configuration ofa terminal apparatus according to an embodiment.

FIG. 17 is a block diagram illustrating an example of a detailedconfiguration of a radio communication unit shown in FIG. 16.

FIG. 18 is a flow chart illustrating an example of a flow of bandsetting processing according to an embodiment.

FIG. 19A is a first half of a sequence diagram illustrating an exampleof a flow of communication control processing according to anembodiment.

FIG. 19B is a second half of the sequence diagram illustrating theexample of the flow of the communication control processing according toan embodiment.

FIG. 20 is a flow chart illustrating an example of a flow of schedulingprocessing according to an embodiment.

DESCRIPTION OF EMBODIMENTS

Hereinafter, preferred embodiments of the present invention will bedescribed in detail with reference to the appended drawings. Note that,in this specification and the drawings, elements that have substantiallythe same function and structure are denoted with the same referenceindicators, and repeated explanation is omitted.

Furthermore, description will be provided in the following order.

1. Outline of system1-1. Nodes constituting system1-2. Configuration of resource

1-3. Band-filling

1-4. Various settings of extension band1-5. Arrangement of main channels1-6. Identification of resource1-7. Suppression in noise or interference3. Configuration example of base station4. Configuration example of terminal apparatus5. Flow of processing5-1. Band setting processing5-2. Communication control processing5-3. Scheduling processing

6. Summary <1. Outline of System>

First, using FIG. 1 to FIG. 3, an outline of an LTE system will bedescribed.

[1-1. Nodes Constituting System]

FIG. 1 is an explanatory diagram for explaining the outline of the LTEsystem. With reference to FIG. 1, an LTE system 1 includes one or morebase stations 10, one or more terminal apparatuses 12, and a corenetwork (CN) 16.

The base station 10 is a communication control apparatus also called anevolved node B (eNB) in the LTE. The base station 10 provides radiocommunication service for the terminal apparatus 12 positioned within acell 11. The base station 10 is connected to the core network 16. Theterminal apparatus 12 is a radio communication apparatus also called asuser equipment (UE) in the LTE. The terminal apparatus 12 is connectedto the base station 10, and performs radio communication. The basestation being currently connected by the terminal apparatus 12 is calleda serving base station of the terminal apparatus 12. The serving basestation executes various control such as scheduling, rate control,resending control and transmission power control for the individualterminal apparatuses 12. The core network 16 is also called an evolvedpacket core (EPC) in the LTE, and includes various control nodes such asa mobility management entity (MME), a PDN-gateway (P-GW) and aserving-gateway (S-GW) (not shown). The MME manages mobility of theterminal apparatus 12. The S-GW is a gateway transferring a packet of auser plane for the terminal apparatus 12. The P-GW is a gatewaypositioned at a connection point between the core network 16 and apacket data network (PDN) 17. The PDN 17 may include an IP network suchas the Internet and an enterprise network.

[1-2. Configuration of Resource]

A radio link from the base station 10 to the terminal apparatus 12 is adownlink (DL). A radio link from the terminal apparatus 12 to the basestation 10 is an uplink (UL). In the LTE, a group of frequency bandsincluding various control channels and data channels defined to realizethe radio communication service are called a component carrier. When theLTE system operates on a frequency division duplex (FDD) scheme, thecomponent carrier in the downlink (downlink CC) and the componentcarrier in the uplink (uplink CC) are separate frequency bands. When theLTE system operates on a time division duplex (TDD) scheme, bothdownlink transmission and uplink transmission are performed on the onecomponent carrier.

FIG. 2 is an explanatory diagram for explaining an example of aconfiguration of a downlink resource. In an upper part of FIG. 2, oneradio frame having the length of 10 msec is shown. The one radio frameincludes 10 sub-frames each having the length of 1 msec. The onesub-frame includes two 0.5 ms slots. The one 0.5 ms slot normallyincludes 7 OFDM symbols (6 OFDM symbols when an extension cyclic prefixis used) in a time direction. Then, the one OFDM symbol and 12subcarriers in a frequency direction constitute one resource block. In 6resource blocks positioned on the center of the component carrier in thefrequency direction among such time-frequency resources, a resource anda broadcast channel (BCH) for transmitting a synchronization signal arearranged. In this specification, the resource for transmitting thesynchronization signal is called a synchronization resource. Theterminal apparatus receives a primary synchronization signal and asecondary synchronization signal on the synchronization resource inorder to establish synchronization with the base station in a cellsearch procedure. The broadcast channel is used for broadcasting amaster information block (MIB). The MIB conveys static broadcastinformation such as a bandwidth of the component carrier and the numberof antennas of the base station. Note that dynamic broadcast informationis conveyed by a system information block (SIB) on a downlink sharedchannel (DL-SCH). The remaining resource blocks may be used for datatransmission in the downlink.

FIG. 3 is an explanatory diagram for explaining an example of aconfiguration of an uplink resource. Also in the uplink, one radio frameincludes 10 sub-frames each having the length of 1 msec. The onesub-frame includes 2 0.5 ms slots. In the center in the time directionof each of the 0.5 ms slots, a reference sequence used by the basestation for demodulating an uplink signal is arranged. A random accesschannel (PRACH) is used by the terminal apparatus for transmitting arandom access signal (random access preamble) to the base station. Theterminal apparatus acquires which of the resource blocks the randomaccess channel is assigned to by receiving the SIB (more specifically,SIB2 of SIB1 to SIB 8). A physical uplink control channel (PUCCH) isused by the terminal apparatus for transmitting an uplink controlsignal. A physical uplink shared channel (PUSCH) is used by the terminalapparatus for transmitting an uplink data signal. The PUCCH is arrangedin a band end of the component carrier for allowing more continuousresource blocks to be assigned to the terminal apparatus on the PUSCH.This prevents a peak-to-average power ratio (PAPR) of the uplink datasignal from increasing to deteriorate power efficiency.

Note that, also in the LTE of the TDD scheme, one radio frame includes10 sub-frames each having the length of 1 msec. However, some of the 10sub-frames are downlink sub-frames, and some other sub-frames are uplinksub-frames.

The base station controls radio communication performed by the terminalapparatus in a resource block unit for both of the downlink resource andthe uplink resource. This is applied not only to the FDD but to the TDD.For example, resource assignment information transmitted from the basestation to the terminal apparatus identifies the resource block to beassigned by using a unique resource block number in a frequency domain.In this specification, the resource assignment information may includescheduling information indicating resource assignment (DL assignment andUL grant) for data transmission, and channel arrangement informationindicating an arrangement of the control channels. The channelarrangement information is, for example, information for indicating thearrangement of the PRACH described above to the terminal apparatus.

[1-3. Band Filling]

The table 5.6-1 of Non-Patent Literature 1 defines 6 alternatives of thebandwidth of the component carrier in the LTE. According to thedefinition, the bandwidths of the component carrier include 1.4 MHz, 3MHz, 5 MHz, 10 MHz, 15 MHz and 20 MHz. These bandwidths are called abasic bandwidth in this specification. However, frequency bands assignedto communication providers in each country are not always adapted tothese basic bandwidths.

FIG. 4A is an explanatory diagram for explaining a first example of thearrangement of the component carrier in the frequency domain. In thefirst example, a frequency band of 4 MHz can be used for a provider.Note that, for convenience of the description, only one link directionis considered. When the provider sets a component carrier C0 having thebasic bandwidth of 3 MHz to the frequency band that can be used, anexcess band having a bandwidth of 1 MHz remains. However, since thebandwidth of 1 MHz is less than any basic bandwidth, this excess band isnot utilized.

FIG. 4B is an explanatory diagram for explaining a second example of thearrangement of the component carrier in the frequency domain. In thesecond example, a frequency band of 12 MHz can be used for a provider.When the provider sets component carriers C11, C12, C13 and C14 eachhaving the basic bandwidth of 3 MHz to the frequency band that can beused, and applies carrier aggregation to these component carriers, anexcess band is not generated. This solution seemingly appears to beoptimal in terms of utilization efficiency of the frequency resource.However, all the terminal apparatuses do not support the carrieraggregation, and the terminal apparatus that does not support thecarrier aggregation can use only the one component carrier. Therefore,the solution of FIG. 4B practically includes a waste of the resource(the terminal apparatus that does not support the carrier aggregationcannot use a bandwidth of 9 MHz). Therefore, the provider may hope toset the single component carrier having the wider basic bandwidth.Further, since the carrier aggregation in the LTE-A has a restrictionthat intervals between the center frequencies of the multiple CCs mustbe the integer multiple of 300 kHz, an optimal arrangement of thecomponent carrier may be realized only in a limited case.

FIG. 4C is an explanatory diagram for explaining a third example of thearrangement of the component carrier in the frequency domain. Also inthe third example, the frequency band of 12 MHz can be used for aprovider. Unlike the second example, when the provider sets a componentcarrier C10 having the basic bandwidth of 10 MHz, the terminal apparatuscan use the component carrier C10 regardless of whether it supports thecarrier aggregation. However, with the solution of FIG. 4C, an excessband having a bandwidth of 2 MHz remains.

The band-filling is a concept for utilizing the excess frequency band asexemplified in FIG. 4A and FIG. 4C as the extension band for extendingthe bandwidth of the component carrier. However, there are some problemsin the band-filling.

(1) Overhead of Control Signal

A bandwidth of the excess frequency band is normally assumed to besmaller than the basic bandwidth. Therefore, when a control resource(for example, a synchronization resource, a broadcast channel and otherchannels for a control signal) for allowing the terminal apparatus touse the extension band is arranged in the extension band, a rate ofoverhead of the resource for the control signal is relatively increased.

(2) Notification of Extension Bandwidth

When the component carrier and the extension band added to the componentcarrier are handled as one frequency band, the total bandwidth does notcorrespond to the specified 6 basic bandwidths in most cases. On theother hand, bandwidth information broadcasted to the terminal apparatusin the existing MIB can only indicate any of the 6 basic bandwidths.Modification of the bandwidth information hinders a normal operation ofthe terminal apparatus that does not support radio communication on theextension band (hereinafter, referred to as a legacy terminal).Therefore, it is desirable to introduce a new information element fornotifying the terminal apparatus of a bandwidth of the extension band(hereinafter, referred to as an extension bandwidth) without modifyingthe bandwidth information for the basic bandwidth in the MIB. However,if the extension bandwidth can take any value, the number of bits of thenew information element may increase excessively.

(3) Compatibility with Legacy Terminal

As described above, the resource assignment information transmitted fromthe base station to the terminal apparatus identifies the individualresources in the resource block unit. Normally, the resource blocknumbers are granted to the resource blocks in the increasing order ofthe frequency. However, when the resource block numbers smaller thanthose of the component carrier are granted to the resource blocks in theextension band in the case where the extension band is set to a lowerside (a lower side of the frequency) of the component carrier, thelegacy terminal may misunderstand that the resource block numbers pointto the resource blocks in the component carrier.

(4) Complexity of Transmitter-Receiver

Since there are only 6 alternatives of the basic bandwidth in the LTE, atransmitter-receiver as an apparatus receiving radio signals of the LTEonly may be designed so as to handle the 6 basic bandwidths.Specifically, circuit parameters such as a sampling rate, a cut-offfrequency of a low-pass filter and a fast Fourier transform (FFT) sizemay depend on a transmitting and receiving band (and a bandwidththereof). However, when the extension bandwidth is set to any value, thetransmitter-receiver will be required to be designed so as to correctlyoperate for every setting value of the extension band, resulting in aremarkable increase in implementation cost of the apparatus.

(5) Deterioration in Reception Quality of Legacy Terminal

When the extension band is set to the excess frequency band adjacent tothe downlink CC, the legacy terminal recognizes a signal received on theextension band as noise. The low-pass filter of the transmitter-receiverof the legacy terminal cannot thoroughly remove this noise received at afrequency close to that of a desired signal. Therefore, the transmissionof the radio signal on the extension band may deteriorate receptionquality in the legacy terminal.

(6) Time of Cell Search

According to the procedure of the existing cell search, the terminalapparatus can detect the synchronization signal by using as a clue thefact that the synchronization signal is transmitted in the band centerof the downlink CC. However, when the extension band is set, thesynchronization signal does not always exist in the center of the bandincluding the downlink CC and the extension band. If the position of thesynchronization signal is unclear, the terminal apparatus cannot helpsearching for the synchronization signal blindly to elongate a timebefore it is detected.

(7) Interference Caused by Extension Band

When a radio signal is transmitted on the extension band in a certaincell, the radio signal may cause inter-cell interference in adjacentcells. The base station in the LTE has a system called inter-cellinterference coordination (ICIC) for suppressing the inter-cellinterference, but since the current ICIC is not designed inconsideration of the band-filling, it is beneficial to introduce anadditional system for suppressing the inter-cell interference caused bythe extension band.

(8) Discontinuity of Uplink Resource

As described above, the PUCCH used by the terminal apparatus to transmitthe uplink control signal is arranged in the band end of the componentcarrier in order to make it possible to assign more continuous resourceblocks to the terminal apparatus on the PUSCH. However, when theextension band is set to the outside of the band of the componentcarrier, the PUSCH of the component carrier and the channel in theextension band become discontinuous across the PUCCH.

The technology according to the present disclosure is provided forsolving or reducing at least one of the problems assumed related to theband-filling as described here.

[1-4. Setting Patterns of Extension Band]

FIG. 5A to FIG. 5C are explanatory diagrams illustrating 3 settingpatterns of the extension band, respectively. These setting patterns aredistinguished by a positional relationship between the component carrierand the extension band added to the component carrier. A first settingpattern is one-side setting, a second setting pattern is both-sidesymmetric setting, and a third setting pattern is both-side asymmetricsetting.

(1) One-Side Setting

FIG. 5A illustrates an example of the one-side setting. According to theone-side setting, the extension band is added to the component carrieronly in the excess frequency band on either the upper side or the lowerside of the component carrier. With reference to FIG. 5A, a downlink CCDC11 and an uplink CC UC14 are arranged in a band from a frequency F11to a frequency F12 and in a band from a frequency F15 to a frequencyF16, respectively. An extension band EB13 is an extension band added tothe downlink CC DC11. The extension band EB13 occupies a band from afrequency F13 to a frequency F14 on the upper side of the downlink CCDC11. An extension band EB15 is an extension band added to the uplink CCUC14. The extension band EB15 occupies a band from a frequency F16 to afrequency F17 on the upper side of the uplink CC UC14.

A gap between the upper end frequency F12 of the downlink CC DC11 andthe lower end frequency F13 of the extension band EB13 is used as aguard band GB12. In the guard band, a radio signal is not transmitted.As a result of the arrangement of such a guard band, thetransmitter-receiver of the legacy terminal can suppress the noise orinterference caused by the radio signal on the extension band, forexample, by using a filter. Note that, since the guard band is a bandthat is not used for transmission of the radio signal, the arrangementof the guard band has a negative effect in terms of resource utilizationefficiency. However, according to the one-side setting as exemplified inFIG. 5A, it is enough to arrange only the one guard band on either theupper side or the lower side of the downlink CC. Therefore, it can besaid that the one-side setting is an effective setting pattern realizingan appropriate balance between the avoidance of deterioration inreception quality of the legacy terminal and the resource utilizationefficiency. Further, the one-side setting is also a setting patternallowing more continuous shared channels to be arranged in the extensionband in the uplink, compared with the both-side setting to be describedlater. Since the base station receiving the uplink signal knows theexistence of the extension band, the guard band may not be arrangedbetween the uplink CC UC14 and the extension band EB15.

In a certain embodiment, the extension band is set so as to have theextension bandwidth of the integer multiple of the size of the resourceblock. As described above, one resource block has 12 subcarriers in thefrequency direction. Since the subcarriers are arranged at frequencyintervals of 15 kHz, the size of the one resource block in the frequencydirection (hereinafter, referred to as an RB size) is 180 kHz. Withreference to the example of FIG. 5B, the extension band EB13 occupies 6resource blocks in the frequency direction (F14−F13=6×180=1080 [kHz]).The guard band GB12 occupies 2 resource blocks in the frequencydirection (F13−F12=2×180=360 [kHz]). The extension band EB15 occupies 8resource blocks in the frequency direction (F17−F16=8×180=1440 [kHz]).

The arrangement of the extension band in the resource block unit in thismanner allows the extension band to be expressed by the number of theresource blocks. This makes it possible to notify the terminal apparatusof the extension band with a small number of bits by using an indexbased on the number of the resource blocks (for example, the number ofthe resource blocks itself, a code mapped to the number of the resourceblocks, or any value calculated from the number of the resource blocks).

The guard band may be arranged in the resource block unit (that is, soas to have the bandwidth of the integer multiple of the RB size), or maybe arranged, for example, in a subcarrier unit (that is, so as to havethe bandwidth of the integer multiple of 15 kHz). The terminal apparatusmay be explicitly notified of the setting of the guard band. Instead,the notification of the setting of the guard band may be omitted by, forexample, specifying the bandwidth in advance. Further, when the guardband is arranged in the resource block unit, the bandwidth of the guardband may be a part of the extension bandwidth reported to the terminalapparatus. In this case, even when the bandwidth of the guard band isnot explicitly reported, for example, when the base station does notschedule the downlink transmission on the guard band, it is possible tosubstantially realize the guard band without making the terminalapparatus notice the existence of the guard band. This can reduceoverhead of information required for the notification of the guard band,and makes it easy for the base station to dynamically change thebandwidth of the guard band.

(2) Both-Side Symmetric Setting

FIG. 6A illustrates an example of the both-side symmetric setting.According to the both-side symmetric setting, the extension bands aresymmetrically added to the component carrier in the excess frequencybands on the upper side and the lower side of the component carrier.With reference to FIG. 6A, a downlink CC DC23 and an uplink CC UC27 arearranged in a band from a frequency F22 to a frequency F23 and in a bandfrom a frequency F27 to frequency F28, respectively. An extension bandEB21 is a lower-side extension band added to the downlink CC DC23. Theextension band EB21 occupies a band from a frequency F20 to a frequencyF21. A guard band GB 22 is arranged between the extension band EB21 andthe downlink CC DC23. An extension band EB25 is an upper-side extensionband added to the downlink CC DC23. The extension band EB25 occupies aband from a frequency F24 to a frequency F25. A guard band GB 24 isarranged between the downlink CC DC23 and the extension band EB25. Anextension band EB26 is a lower-side extension band added to the uplinkCC UC27. The extension band EB26 occupies a band from a frequency F26 toa frequency F27. An extension band EB28 is an upper-side extension bandadded to the uplink CC UC27. The extension band EB28 occupies a bandfrom a frequency F28 to a frequency F29. In the uplink, the guard bandmay not be arranged.

Also in the both-side symmetric setting, when a radio signal is nottransmitted in the guard band between the downlink CC and the twoextension bands, it is possible to suppress noise or interference in areception circuit of the legacy terminal to avoid deterioration inreception quality. Further, the both-side symmetric setting has aneffect being more advantageous than the one-side setting described abovein terms of a cell search procedure to be described later.

In a certain embodiment, the extension band is set so as to have theextension bandwidth of the integer multiple of the size of the resourceblock. With reference to the example of FIG. 6B, the extension bandsEB21 and EB25 occupy 6 resource blocks in the frequency direction. Theguard bands GB22 and G24 occupy 2 resource blocks in the frequencydirection. The extension bands EB26 and EB28 occupy 8 resource blocks inthe frequency direction. When the extension blocks are arranged in theresource block unit in this manner, it is possible to express theextension bandwidth by the number of the resource blocks. This makes itpossible to notify the terminal apparatus of the extension bandwidthwith a small number of bits by using the index based on the number ofthe resource blocks. In the both-end symmetric setting, since theextension bands on both sides of the component carrier have the sameextension bandwidth, it is enough for the terminal apparatus to benotified of only information on one extension bandwidth for the twoextension bands.

The guard bands may be symmetrically arranged in the resource blockunit, or may be symmetrically arranged in the subcarrier unit. Theterminal apparatus may be explicitly notified of the setting of theguard bands, or may not be notified of the setting of the guard bands.Further, in the case where the guard bands are arranged in the resourceblock unit, when the terminal apparatus is not explicitly notified ofthe bandwidth of the guard band, and, for example, when the base stationdoes not schedule the downlink transmission on the guard band, the guardband may be substantially realized. This can reduce the overhead of theinformation required for the notification of the guard band, and canmake it easy for the base station to dynamically change the bandwidth ofthe guard band.

(2) Both-Side Asymmetric Setting

FIG. 7A illustrates an example of the both-side asymmetric setting.According to the both-side asymmetric setting, the extension bands areasymmetrically added to the component carrier in the excess frequencybands on the upper side and the lower side of the component carrier.With reference to FIG. 7A, a downlink CC DC33 and an uplink CC UC37 arearranged in a band from a frequency F32 to a frequency F33 and in a bandfrom a frequency F37 to frequency F38, respectively. An extension bandEB21 is a lower-side extension band added to the downlink CC DC33. Theextension band EB31 occupies a band from a frequency F30 to a frequencyF31. A guard band GB 32 is arranged between the extension band EB31 andthe downlink CC DC33. An extension band EB35 is an upper-side extensionband added to the downlink CC DC33. The extension band EB35 occupies aband from a frequency F34 to a frequency F35. A guard band GB 34 isarranged between the downlink CC DC33 and the extension band EB35. Anextension band EB36 is a lower-side extension band added to the uplinkCC UC37. The extension band EB36 occupies a band from a frequency F36 toa frequency F37. An extension band EB38 is an upper-side extension bandadded to the uplink CC UC37. The extension band EB38 occupies a bandfrom a frequency F38 to a frequency F39. In the uplink, the guard bandmay not be arranged.

Also in the both-side asymmetric setting, when a radio signal is nottransmitted in the guard band between the downlink CC and the twoextension bands, it is possible to suppress noise or interference in areception circuit of the legacy terminal to avoid deterioration inreception quality. Further, the both-side asymmetric setting has aneffect being more advantageous than the one-side setting described abovein terms of a cell search procedure to be described later.

In a certain embodiment, the extension band is set so as to have theextension bandwidth of the integer multiple of the size of the resourceblock. With reference to the example of FIG. 7B, the extension band EB31occupies 4 resource blocks in the frequency direction. The guard bandsGB32 and GB34 occupy 2 resource blocks in the frequency direction. Theextension bands EB35 occupies 8 resource blocks in the frequencydirection. The extension bands EB36 occupies 6 resource blocks in thefrequency direction. The extension bands EB38 occupies 10 resourceblocks in the frequency direction. When the extension blocks arearranged in the resource block unit in this manner, it is possible toexpress the extension bandwidth by the number of the resource blocks.This makes it possible to notify the terminal apparatus of the extensionbandwidth with a small number of bits by using the index based on thenumber of the resource blocks. Also in the both-end asymmetric setting,when the terminal apparatus is not explicitly notified of the bandwidthof the guard band, the overhead of the information required for thenotification of the guard band may be reduced.

When the excess frequency bands having bandwidths different from eachother exist on the upper side and the lower side of the componentcarrier, the both-side asymmetric setting is a flexible setting patternallowing the excess frequency bands to be utilized without being wasted.

[1-5. Arrangement of Main Channels] (1) Downlink

Even when any setting pattern is selected, by using the synchronizationresource of the component carrier for allowing the terminal apparatus tobe synchronized with the extension band, it is possible to avoid anincrease in overhead of the resource required for transmission of thesynchronization signal. In this case, the base station operates thecomponent carrier and the extension band added to the component carrierin time synchronization with each other. Further, control informationsuch as the broadcast information referred to by the terminal apparatusto use the extension band may be also transmitted on the componentcarrier instead of the extension band.

FIG. 8A is an explanatory diagram for explaining an example of anarrangement of the synchronization resource and the broadcast channel inthe one-side setting. With reference to FIG. 8A, the downlink CC DC11and the extension band EB13 on the upper side of the downlink CC DC11are shown. In 6 resource blocks in the center of the downlink CC DC11,the synchronization resource for transmitting the primarysynchronization signal and the secondary synchronization signal isarranged. This synchronization resource of the downlink CC DC11 is usedalso for allowing the terminal apparatus to be synchronized with theextension band EB13. In this manner, when the synchronization resourceis used in common between the component carrier and the extension band,both of the legacy terminal and a non-legacy terminal will have only tosearch for the synchronization signal on the synchronization resource ofthe component carrier in the procedure of the cell search. Therefore,without modifying implementation of the procedure of the existing cellsearch, it is possible to implement the non-legacy terminal. Further,even when the extension bandwidth is less than the minimum basicbandwidth, it is possible to allow the terminal apparatus to beappropriately synchronized with the extension band by using thesynchronization resource arranged in the component carrier instead ofthe extension band.

In the resource blocks positioned at the same frequency as that of thesynchronization resource, a physical broadcast channel (PBCH) fortransmitting the broadcast information is arranged. The PBCH is aphysical channel corresponding to the BCH. For example, band-filling(BF) setting information indicating the extension bandwidth and the likemay be broadcasted in the MIB on the PBCH. Further, the BF settinginformation may be broadcasted in the SIB on the PDSCH. Instead, the BFsetting information may be transmitted to the individual terminalapparatuses on the PDCCH. In this manner, the setting informationrelated to the extension band is transmitted on the downlink CC, thenon-legacy terminal can acquire the setting of the extension band byfirst establishing the synchronization with the downlink CC, and thenreceiving the setting information on the component carrier. This makesit possible to smoothly transfer an operation from an operation state inwhich the band-filling is not performed to an operation state in whichthe band-filling is performed.

Furthermore, scheduling information on the resource blocks in theextension band, along with scheduling information on the resource blocksin the component carrier, may be transmitted to the terminal apparatuson the PDCCH of the downlink CC DC11. This makes it possible to reduceoverhead of the resource required for transmission of the schedulinginformation. Further, acknowledge (ACK)/negative acknowledge (NACK) touplink transmission on the extension band in the uplink may betransmitted to the terminal apparatus on a physical hybrid-ARQ indicatorchannel (PHICH) of the downlink CC DC11. When uplink transmission isperformed on the uplink CC and the extension band in the uplink, theACK/NACK to the uplink transmission may be processed and combined in thesame HARQ processes in the base station and transmitted to the terminalapparatus. This makes it possible to reduce overhead of the resourcerequired for transmission of the ACK/NACK.

FIG. 8B is an explanatory diagram for explaining an example of anarrangement of the synchronization resource and the broadcast channel inthe both-side symmetric setting. With reference to FIG. 8B, the downlinkCC DC23 and the extension band EB21 and EB25 on the upper side of thedownlink CC DC23 are shown. In 6 resource blocks in the center of thedownlink CC DC23, the synchronization resource for transmitting theprimary synchronization signal and the secondary synchronization signalis arranged. This synchronization resource of the downlink CC DC23 isused also for allowing the terminal apparatus to be synchronized withthe extension band EB21 and EB25. In this manner, when thesynchronization resource is used in common between the component carrierand the extension band, both of the legacy terminal and a non-legacyterminal will have only to search for the synchronization signal on thesynchronization resource of the component carrier in the procedure ofthe cell search. Therefore, without modifying implementation of theprocedure of the existing cell search, it is possible to implement thenon-legacy terminal. Further, even when each extension bandwidth is lessthan the minimum basic bandwidth, it is possible to allow the terminalapparatus to be appropriately synchronized with the extension band byusing the synchronization resource arranged in the component carrierinstead of the extension band.

Furthermore, in the example of FIG. 8B, the synchronization resource ispositioned in the center of the whole band in the downlink, combiningthe downlink CC DC23 and the two extension bands EB21 and EB25.Therefore, both of the legacy terminal and the non-legacy terminal,similarly to the procedure of the existing cell search, can quicklydetect the synchronization signal on the synchronization resourcewithout overlooking the position of the synchronization resource. In theuse application such as roaming in which the terminal apparatuspreviously has no knowledge related to the specific position of thesynchronization resource, such a system that the center arrangement ofthe synchronization resource is maintained is especially beneficial.

In the resource blocks positioned at the same frequency as that of thesynchronization resource, the physical broadcast channel (PBCH) fortransmitting the broadcast information is arranged. For example, the BFsetting information may be broadcasted in the MIB on the PBCH, or may bebroadcasted in the SIB on the PDSCH. Instead, the BF setting informationmay be transmitted to the individual terminal apparatuses on the PDCCH.Similarly to the one-side setting, when the setting information relatedto the extension band is transmitted on the downlink CC, it is possibleto smoothly transfer an operation from an operation state in which theband-filling is not performed to an operation state in which theband-filling is performed.

Furthermore, the scheduling information on the resource blocks in theextension band, along with the scheduling information on the resourceblocks in the component carrier, may be transmitted to the terminalapparatus on the PDCCH of the downlink CC DC23. This makes it possibleto reduce overhead of the resource required for transmission of thescheduling information. Further, the ACK/NACK to uplink transmission onthe extension band in the uplink may be transmitted to the terminalapparatus on the PHICH of the downlink CC DC23. The ACK/NACK to theuplink transmission on the uplink CC and on the extension band in theuplink may be processed by the same HARQ processes. This makes itpossible to reduce overhead of the resource required for transmission ofthe ACK/NACK.

(2) Uplink

As described above, the PUCCH used by the terminal apparatus to transmitthe uplink control signal is arranged in the band end of the uplink CC.When the terminal apparatus transmits the data signal, it is desirableto assign as many continuous resource blocks as possible in the PUSCH tothe terminal apparatus in order to avoid the rise of the PAPR. However,if many of the resources in the PUSCH for transmission of a controlsignal and a random access signal (hereinafter, collectively referred toas a non-data signal) by the non-legacy terminal, it becomes difficultto assign the continuous resource blocks in the PUSCH to the legacyterminal that cannot use the extension band. Then, in a certainembodiment, the transmission of the non-data signals in the uplink bythe non-legacy terminal is preferentially assigned to the extensionband.

FIG. 9A is an explanatory diagram for explaining an example of anarrangement of the uplink control channel in the one-side setting. Withreference to FIG. 9A, the uplink CC UC14 and the extension band EB15 onthe upper side of the uplink CC UC14 are shown. A physical uplinkcontrol channel (PUCCH) Ch11 is arranged in the band end of the uplinkCC UC14. A PUCCH Ch12 may be arranged in the band end of the extensionband EB15. The legacy terminal can use only the uplink CC UC14. Aphysical random access channel (PRACH) Ch13 for the legacy terminal isassigned to the resource blocks in the uplink CC UC14. Therefore, theresource blocks of the PUSCH other than the PUCCH Ch11 and the PRACHCh13 in the uplink CC UC14 can be used for transmission of the datasignal by the legacy terminal. In the example of FIG. 9A, a separatePRACH Ch14 for the non-legacy terminal is assigned to the resourceblocks in the extension band EB15. Accordingly, as many usable (andcontinuous) resource blocks as possible in the PUSCH are left in theuplink CC UC14 for the legacy terminal.

FIG. 9B is an explanatory diagram for explaining an example of anarrangement of the uplink control channel in the both-side symmetricsetting. With reference to FIG. 9B, the uplink CC UC27, and theextension bands EB26 and EB 28 on the upper side and the lower side ofthe uplink CC UC27 are shown. A PUCCH Ch21 is arranged in the band endof the uplink CC UC27. A PUCCH Ch22 may be arranged in the band ends ofthe extension bands EB26 and EB28. A PRACH Ch23 for the legacy terminalis assigned to the resource blocks in the uplink CC UC27. In the exampleof FIG. 9B, a separate PRACH Ch24 for the non-legacy terminal isassigned to the resource blocks in the extension band EB28. Accordingly,as many usable (and continuous) resource blocks as possible in the PUSCHare left in the uplink CC UC27 for the legacy terminal.

In this manner, when the PUCC and PRACH for the non-legacy terminal(channels for the non-data signal) are preferentially assigned to theextension band in the uplink instead of the uplink CC, it is possiblefor the legacy terminal to successfully transmit the uplink data signalby using more continuous resource blocks in the PUSCH. Further, whenseparate random access channels are prepared in the legacy terminal andthe non-legacy terminal, respectively, the possibility of collision ofthe random access signal may be reduced to improve throughput of thesystem.

The legacy terminal may be notified of the arrangement of the PRACH forthe non-legacy terminal described using FIG. 9A and FIG. 9B, separatelyfrom the channel arrangement information on the arrangement of the PRACHfor the legacy terminal, conveyed on the SIB2. This new channelarrangement information may be broadcasted using a new informationelement of the SIB in the downlink CC exemplified in FIG. 8A or FIG. 8B,or may be transmitted to the individual terminal apparatuses on thePDCCH.

Furthermore, the ACK/NACK to downlink transmission on the downlink CCand the extension band in the downlink may be processed and combined inthe same HARQ processes in the terminal apparatus and transmitted to thebase station. This makes it possible to reduce overhead of the resourcerequired for transmission of the ACK/NACK. Note that the ACK/NACK to thedownlink transmission may be transmitted on the PUCCH or the PUSCH.

It should be appreciated that some features related to the arrangementof the channels described in this section may be applied to theboth-side asymmetric setting.

[1-6. Identification of Resources] (1) Numbering Rule

As described above, normally, in the resource assignment informationtransmitted from the base station to the terminal apparatus, theindividual resources are identified by using the resource block numbersgranted to the resource blocks in the increasing order of the frequency.When the extension band is added to the component carrier, it isdesirable that the resource block number is unique through the componentcarrier and the extension band. However, the extension band is set tothe band on the lower side of the component carrier, when the numbersare granted to the resource blocks in the increasing order of thefrequency, the numbers granted to the resource blocks in the extensionband on the lower side are set to be smaller than the numbers granted tothe resource blocks in the component carrier. FIG. 10A illustrates anexample of such a situation. In the example of FIG. 10A, an extensionband EB41 includes 6 resource blocks having the resource block numbersfrom “0” to “5”, respectively. A downlink CC DC43 includes 16 resourceblocks having the resource block numbers from “6” to “21”, respectively.An extension band EB45 includes a plurality of resource blocks havingthe resource block numbers equal to or more than a resource block number22, respectively. Note that the number of the resource blocks in each ofthe component carrier and the extension band is merely an example fordescription. Each band may include more resource blocks or less resourceblocks.

According to the existing numbering rule exemplified in FIG. 10A, theresource block numbers granted to the resource blocks in the componentcarrier are changed depending on the bandwidth of the extension band onthe lower side of the component carrier. As a result, there is apossibility that the legacy terminal will misunderstand that the smallresource block numbers granted to the resource blocks in the extensionband EB41 point to the resource blocks in the component carrier DC43.When the legacy terminal falsely interprets the resource block numbers,radio communication by the legacy terminal would not operate correctly.Then, in a certain embodiment, a number rule is adopted in which theresource block numbers are uniquely granted to the respective resourceblocks through the component carrier and the extension band, andhowever, the resource block numbers smaller than those of the resourceblocks included in the extension band are granted to any resource blocksincluded in the component carrier. This makes it possible to solve therisk that the legacy terminal misunderstands the meaning of the resourceblock numbers.

FIG. 10B is an explanatory diagram for explaining a first example of thenew numbering rule of the resource block numbers. With reference to FIG.10B, similarly to FIG. 10A, the downlink CC DC43, the extension bandEB41 on the lower side of the downlink CC DC43, and the extension bandEB45 on the upper side of the downlink CC DC43 are shown. A guard bandGB42 exists between the extension band EB41 and the downlink CC DC43. Aguard band GB44 exists between the downlink CC DC43 and the extensionband EB45. According to the first example of the numbering rule, theresource block numbers are granted to the one or more resource blocks inthe downlink CC DC43 in the increasing order of the frequency from zero.In the example of FIG. 10B, the resource block numbers from “0” to “15”are granted to 16 resource blocks in the downlink CC DC43, respectively.Further, the resource block numbers from “16” to “N−1” are granted tothe resource blocks in the extension band EB45 and the extension bandEB41, respectively, (N equals to the total of the number of the resourceblocks included in the extension bands). In the first example, theexistence of the guard band is not considered in the numbering of theresource block numbers.

FIG. 10C is an explanatory diagram for explaining a second example ofthe new numbering rule of the resource block number. Also in the secondexample of the numbering rule, the resource block numbers are granted tothe one or more resource blocks in the downlink CC DC43 in theincreasing order of the frequency from zero. In the example of FIG. 10C,the resource block numbers from “0” to “15” are granted to 16 resourceblocks in the downlink CC DC43, respectively. Further, the resourceblock numbers from “16” to “M−1” are granted to the resource blocks inthe guard band GB44, the extension band EB45 and the extension band EB41and the guard band GB42, respectively, (M equals to the total of thenumber of the resource blocks included in the extension bands and theguard bands).

In the first example and the second example of the numbering ruledescribed above, the legacy terminal identifies the resource blocks inthe downlink CC DC43 by using the resource block numbers from “0” to“15”. These resource block numbers are not changed depending on where ornot the extension band is set, and the bandwidth of the extension band.Therefore, it is possible to solve the risk that the legacy terminalmisunderstands the meaning of the resource block numbers, to securebackward compatibility.

Note that, in the FIG. 10B and FIG. 10C, the example that the resourceblock numbers smaller than those of the extension band on the lower sideare granted to the resource blocks included in the extension band on theupper side has been described, but the numbering rule is not limited tosuch an example. That is, the resource block numbers smaller than thoseof the extension band on the upper side may be granted to the resourceblocks included in the extension band on the lower side. Further, itshould be appreciated that the numbering rule described here can be alsoapplied to the one-side setting and the both-side symmetric setting.

(2) BF Setting Information

FIG. 11 is an explanatory diagram for explaining an example of the BFsetting information. As described using FIG. 8A and FIG. 8B, the BFsetting information is control information for notifying the non-legacyterminal of the setting of the extension band. With reference to FIG.11, the BF setting information includes 6 data items of an “extensiondirection”, a “bandwidth 1”, a “bandwidth 2”, a “guard bandwidth”, and a“channel arrangement”.

The “extension direction” is a division identifying the setting patternof the extension band. As an example, a value “0” or “1” of the“extension direction” indicates the one-side setting, and when the valueis “0”, the extension band is set on the upper side of the componentcarrier, and when the value is “1”, the extension band is set on thelower side of the component carrier. A value “2” of the “extensiondirection” indicates the both-side symmetric setting. A value “3” of the“extension direction” indicates the both-side asymmetric setting. Notethat, when only the one-side setting can be selected as a restriction ofthe system, the “extension direction” may be a 1-bit flag indicating thevalue “0” or “1”. When only the both-side symmetric setting can beselected as the restriction of the system, the BF setting informationmay not include the “extension direction” as an information element.

The “bandwidth 1” indicates a bandwidth of a first extension band. The“bandwidth 2” indicates a bandwidth of a second extension band. In theone-side setting, the “bandwidth 2” is omitted. Also in the both-sidesymmetric setting, the “bandwidth 2” is omitted, and two extension bandseach having an extension bandwidth indicated by the “bandwidth 1” areset on both sides of the component carrier. In a certain embodiment,these “bandwidth 1” and “bandwidth 2” are an index based on the numberof the resource blocks corresponding to the extension bandwidth. Forexample, when the extension bandwidth is 180 kHz×N_(EB) (N_(EB) is aninteger of one or more), the “bandwidth 1” or the “bandwidth 2” canindicate N_(EB). Instead, the “bandwidth 1” or the “bandwidth 2” mayindicate a code mapped to N_(EB), or any value calculated from N_(EB).Note that the BF setting information may include the “extensiondirection”, the “bandwidth 1” and the “bandwidth 2” for each of thedownlink and the uplink.

The “guard bandwidth” indicates information indicating a bandwidth ofthe guard band arranged between the downlink CC and the extension band.When the bandwidth of the guard band equals to the integer multiple ofthe RB size, the “guard bandwidth” may be an index based on the numberof the resource blocks corresponding to the guard bandwidth. Further,when the bandwidth of the guard band equals to the integer multiple ofthe bandwidth for each subcarrier, the “guard bandwidth” may be an indexbased on the number of the subcarriers corresponding to the guardbandwidth. Note that, when the terminal apparatus is not explicitlynotified of the setting of the guard band, the BF setting informationmay not include the “guard bandwidth” as an information element.

The “channel arrangement” is channel information indicating anarrangement of one or more control channels for the non-legacy terminal.The channel information may indicate, for example, an arrangement of thePUCCH and the PRACH for the non-legacy terminal, arranged separatelyfrom the channels for the legacy terminal. Note that, when the separatecontrol channels are not arranged for the non-legacy terminal, the BFsetting information may not include such channel arrangementinformation.

(3) Resource Assignment Information

In a certain embodiment, the base station transmits the resourceassignment information generated based on the resource block numbersgranted to the respective resource blocks according to the new numberingrule described above to the terminal apparatus. The channel arrangementinformation described using FIG. 11 is an example of the resourceassignment information. Another example of the resource assignmentinformation is the scheduling information indicating the resource blocksassigned to each terminal apparatus for data transmission.

In an example of a specification of the LTE, the scheduling informationspecifies a start number and the number of blocks of a set of theresource blocks to be assigned to the terminal apparatus to identify theassigned resource blocks. In such an information format, the non-legacyterminal is designed so as to handle a start number exceeding the numberof the resource blocks and the number of blocks exceeding the number ofthe resource blocks. This allows the scheduling information for thenon-legacy terminal to identify the resource blocks included in theextension band. For example, on the premise of the example of FIG. 10B,when the scheduling information indicates a start number “16” and “thenumber of blocks” 2, the two resource blocks in the lower end of theextension band EB45 are identified.

In another example of the specification of the LTE, the schedulinginformation identifies a set of the resource blocks to be assigned tothe terminal apparatus by a bitmap format. In such information format,the non-legacy terminal is designed so as to handle a bitmap up to theresource block number larger than the scheduling information to betransmitted to the legacy terminal. This allows the schedulinginformation for the non-legacy terminal to identify the resource blocksincluded in the extension band. For example, on the premise of theexample of FIG. 10B, the scheduling information to be transmitted to thelegacy terminal is generated in a bitmap format of 16 bits in a casewhere the bitmap having the highest granularity is selected. On theother hand, the scheduling information to be transmitted to thenon-legacy terminal is generated in a bitmap format of N bits (N>16) inthe same case. Note that, in any format, the scheduling information isencoded using a terminal-specific identifier (ID) and is transmitted toeach terminal apparatus.

In an example of the specification of the LTE, PRACH arrangementinformation indicating the arrangement of the PRACH is included in theSIB2. The PRACH is a physical channel used by the terminal apparatus totransmit the random access preamble to the base station. The randomaccess preamble is transmitted by the terminal apparatus firstconnecting to the base station, the terminal apparatus recovering from asleep mode, or the terminal apparatus accessing the target base stationin a handover procedure, and, for example, is used to assume a timingoffset unique to the terminal apparatus. The PRACH arrangementinformation includes a frequency offset indicating the arrangement inthe frequency direction of the PRACH (see, for example, “3GPP TS 36.211V11.2.0”, 3GPP, February, 2013). In a certain embodiment, the basestation assigns the PRACH for the non-legacy terminal to the resourceblocks in the extension band, separately from the PRACH for the legacyterminal. The base station then generates the PRACH arrangementinformation indicating the PRACH for the non-legacy terminal, separatelyfrom the PRACH arrangement information for the legacy terminal. ThePRACH arrangement information for the non-legacy terminal may indicatethe frequency offset exceeding the number of the resource blocksincluded in the uplink CC. The non-legacy terminal is designed so as tohandle such PRACH arrangement information for the non-legacy terminal.This allows the PRACH arrangement information for the non-legacyterminal to identify the resource blocks included in the extension band.

Note that, without being limited by the description here, the channelarrangement information indicating the arrangement of the channels otherthan the PRACH may be generated based on the resource block numbersgranted to the respective resource blocks according to the new numberingrule described above.

[1-7. Suppression of Noise or Interference]

In this section, an additional system for suppressing noise orinterference caused by the extension band will be described.

FIG. 12 is an explanatory diagram for explaining a first example of thesystem for suppressing noise or interference. In the first example, thecomponent carrier and the extension band to be added to the componentcarrier are set so as to be overlapped with each other or so that thearrangement of the synchronization resource is sifted between theadjacent cells. With reference to the example of FIG. 12, while anextension band EB52 is set on the upper side of a downlink CC DC51 in acell C1, an extension band EB54 is set on the lower side of a downlinkCC DC53 in an adjacent cell C2 (that is, the positional relationship isreversed between the component carrier and the extension band). Thedownlink CC DC51 has the synchronization resource and the broadcastchannel in a band from a center frequency from F51 to F52 in thefrequency direction. The downlink CC DC53 has the synchronizationresource and the broadcast channel in a band from a center frequencyfrom F53 to F54 in the frequency direction. As a result, the arrangementof the synchronization resource and the broadcast channel is shiftedbetween the adjacent cells. Such non-uniform setting of the extensionband over the multiple cells can prevent the occurrence of theinter-cell inference in the synchronization resource and the mainchannels such as the broadcast channel to realize an stable operation ofthe system.

FIG. 13 is an explanatory diagram for explaining a second example of thesystem for suppressing noise or interference. In the second example, theresource blocks in the extension band in the downlink are assigned fordownlink transmission by the terminal apparatus closer to the center ofthe cell. With reference to FIG. 13, a cell 11 a operated by a basestation 10 a and a cell 11 b operated by a base station 10 b are shown.The cells 11 a and 11 b are adjacent to each other. The terminalapparatus 12 a is the non-legacy terminal positioned inside a centerregion L1 of the cell 11 a. The terminal apparatus 12 b is thenon-legacy terminal positioned around the cell edge of the cell 11 a.The terminal apparatus 12 c is the legacy terminal positioned in thecell 11 a. The terminal apparatus 12 d is the legacy terminal positionedaround the cell edge of the cell 11 b. In such a situation, the basestation 10 a preferentially assigns the resource blocks in the extensionband to the terminal 12 a. Since a distance between the base station 10a and the terminal apparatus 12 a is relatively short, sufficientreception quality can be secured even with small transmission power indownlink transmission to the terminal apparatus 12 a. With the smalltransmission power, the downlink transmission does not adversely affectboth of the legacy terminal 12 c in the serving cell 11 a and the legacyterminal 12 d in the adjacent cell 11 b (see arrows A1 and A2). On theother hand, the base station 10 a preferentially assigns the resourceblocks in the downlink CC to the terminal apparatus 12 b. Since adistance between the base station 10 a and the terminal apparatus 12 bis relatively long, high transmission power may be required in downlinktransmission to the terminal apparatus 12 b. With high transmissionpower in the extension band, the legacy terminal may recognize thedownlink transmission on the extension band as noise or interference.However, when the downlink transmission is performed not on theextension band but on the downlink CC, it is possible to suppress theinterference caused by the downlink transmission in a general receptioncircuit, or control the interference by using an existing interferencecontrol system such as a high interference indicator (HII).

An exemplary embodiment of the basic station and the terminal apparatushaving some of the features described up to here will be described indetail from the next section. Note that the features described above maybe combined in any form regardless of the exemplary embodiment.

<3. Configuration Example of Base Station>

In this section, an example of a configuration of a base station 100according to an embodiment will be described. The base station 100 maybe a macro cell base station or a small cell base station. A small cellis a concept including a femto cell, a nano cell, a pico cell and amicro cell. Further, a part of a function of the base station 100described here may be implemented in the control node in the corenetwork 16 exemplified in FIG. 1.

FIG. 14 is a block diagram illustrating an example of the configurationof the base station 100. With reference to FIG. 14, the base station 100includes a radio communication unit 110, a network communication unit120, a storage unit 130 and a communication control unit 140.

(1) Radio Communication Unit

The radio communication unit 110 is a radio communication interface (ora radio transmitter-receiver) that executes radio communication with oneor more terminal apparatuses. The radio communication unit 110 transmitsand receives a radio signal on a frequency band set by the communicationcontrol unit 140 to be described later. For example, the radiocommunication unit 110 transmits and receives the radio signal to andfrom both of the legacy terminal and the non-legacy terminal on thecomponent carrier having the basic bandwidth. Further, the radiocommunication unit 110 transmits and receives the radio signal to andfrom the non-legacy terminal on the extension band added to thecomponent carrier.

Downlink signals transmitted by the radio communication unit 110 mayinclude a primary synchronization signal and a secondary synchronizationsignal, a broadcast signal, a downlink control signal addressed to theindividual terminals, and a downlink data signal. The primarysynchronization signal and the secondary synchronization signal forallowing the terminal apparatus to be synchronized with the componentcarrier are typically transmitted on the synchronization resourcearranged in 6 resource blocks in the center of the component carrier.The radio communication unit 110 then allows frame timing of theextension band to be synchronized with frame timing of the componentcarrier. This allows the non-legacy terminal to receive the primarysynchronization signal and the secondary synchronization signal on thesynchronization resource of the component carrier to also establishsynchronization with the extension band.

The radio communication unit 110 may transmit the setting informationrelated to the extension band, including the BF setting informationdescribed using FIG. 11, not on the extension band but on the componentcarrier. For example, the BF setting information may be broadcasted tothe terminal apparatus in the MIB on the PBCH or in the SIB on the PDSCHof the component carrier. Instead, the BF setting information may besignaled to the individual terminal apparatuses on the PDCCH of thecomponent carrier.

The radio communication unit 110 can transmit the scheduling informationrelated to the extension band (DL assignment and UL grant) to thenon-legacy terminal not on the extension band but on the PDCCH of thecomponent carrier. This makes it possible to integrate the schedulinginformation on the component carrier and the scheduling information onthe extension band into a group of information (for example, a set of astart number and the number of blocks, or a bitmap). The schedulinginformation to be transmitted to the legacy terminal is not changeddepending on whether or not the extension band is set.

The radio communication unit 110 may transmit the ACK/NACK to uplinktransmission on the extension band in the uplink not on the extensionband but on the PHICH of the component carrier. Further, the radiocommunication unit 110 may transmit the ACK/NACK to downlinktransmission on the extension band in the downlink not on the extensionband but on the PUCCH or the PUSCH of the component carrier.

(2) Network Communication Unit

The network communication unit 120 is a communication interfaceconnected to the core network 16 exemplified in FIG. 1. The networkcommunication 120 relays a communication packet included in an uplinksignal received by the radio communication unit 110 to the core network16. Further, the network communication unit 120 receives a communicationpacket to be transmitted using the downlink signal from the core network16. Further, the network communication unit 120 may exchange a controlsignal between itself and the control node (for example, the MME) on thecore network 16. The network communication unit 120 may exchange thecontrol signal via, for example, an X2 interface between itself and thebase station in the adjacent cell.

(3) Storage Unit

The storage unit 130 stores a program and data for an operation of thebase station 100 by using a storage medium such as a hard disk or asemiconductor memory. The data stored by the storage unit 130 mayinclude, for example, identification information (such as a terminal ID)and capability information for each of the terminal apparatusesconnected to the base station 100. The capability information indicateswhether each terminal apparatus is the non-legacy terminal or the legacyterminal. Positional information (that may be dynamically updated) foreach of the terminal apparatuses may be stored by the storage unit 130.

(4) Communication Control Unit

The communication control unit 140 controls the whole operation of thebase station by using a processor such as a central processing unit(CPU) or a digital signal processor (DSP).

For example, the communication control unit 140 sets the componentcarrier (CC) having the basic bandwidth selected from 6 alternatives of1.4 MHz, 3 MHz, 5 MHz, 10 MHz, 15 MHz and 20 MHz to a usable frequencyband. In the FDD scheme, at least one downlink CC and at least oneuplink CC are set. In the TDD scheme, at least one CC common to thedownlink and the uplink is set. Further, the communication control unit140 controls radio communication performed by the legacy terminal andthe non-legacy terminal on the component carrier, in the resource blockunit. Further, in an embodiment according to the present disclosure, thecommunication control unit 140, when an excess frequency band exists,sets at least one extension band having the extension bandwidth of theinteger multiple of the size of the resource block to at least a part ofthe excess frequency band. The extension band is added to the componentcarrier to extend the bandwidth of the component carrier.

The communication control unit 140, when the extension band is set,generates the BF setting information for notifying the terminalapparatus of the setting of the extension band. As described using FIG.11, the BF setting information may include the division for identifyingthe setting patterns of the extension band, and the bandwidthinformation indicating the extension bandwidth. The bandwidthinformation may be an index based on the number of resourcescorresponding to the extension bandwidth.

When radio communication is performed on the FDD scheme, thecommunication control unit 140 sets the guard band on which radiosignals are not transmitted, to between the downlink CC and theextension band. This reduces deterioration in reception quality in thelegacy terminal, caused by transmission of the downlink signal on theextension band. The communication control unit 140 may explicitly notifythe terminal apparatus of the bandwidth of the guard band, for example,by including information indicating the guard bandwidth into the BFsetting information. Instead, the communication control unit 140 may notexplicitly notify the terminal apparatus of the bandwidth of the guardband. For example, the communication control unit 140 handles a part ofthe extension band as the guard band (in this case, the bandwidth of theguard band is also the integer multiple of the RB size), and preventsthe radio communication unit 110 from transmitting the downlink signalon the guard band (that is, assigns no downlink transmission to theresource blocks included in the implicit guard band), to thereby realizethe guard band. The communication control unit 140 may dynamicallychange the bandwidth of the guard band according to the receptionquality reported from the terminal apparatus. On the other hand, thecommunication control unit 140 sets no guard band to between the uplinkCC and the extension band added to the uplink CC.

FIG. 15A is an explanatory diagram illustrating a first setting exampleof the extension band set by the communication control unit 140. Thesetting pattern in the first setting example is the one-side setting. Inthe first setting example, the usable frequency band is 704 MHz-716 MHzand 734 MHz-746 MHz. For example, the communication control unit 140sets a downlink CC DC61 having the basic bandwidth of 10 MHz to a bandof 734.6 MHz-743.6 MHz, and sets an uplink CC UC64 having the same basicbandwidth of 10 MHz to a band of 704.6 MHz-713.6 MHz. Note that, whenthe basic bandwidth is 10 MHz, since channel gaps are provided on bothends of the component carrier, an effective bandwidth is 9 MHz, and thebandwidth includes 50 resource blocks in the frequency direction.

In the first setting example, the communication control unit 140 sets anextension band EB63 to be added to the downlink CC DC61, to the excessfrequency band on the upper side of the downlink CC DC61. The extensionband EB63 has an extension bandwidth of 1.44 MHz (743.96 MHz-745.4 MHz),and includes 8 resource blocks in the frequency direction. A guard bandGB62 having a bandwidth of 2 resource blocks is set to between thedownlink CC DC61 and the extension band EB63. Further, the communicationcontrol unit 140 sets an extension band EB65 to be added to the uplinkCC UC64 to the excess frequency band on the upper side of the uplink CCUC64. The extension band EB65 has an extension bandwidth of 1.8 MHz(713.6 MHz-715.4 MHz), and includes 10 resource blocks in the frequencydirection. No guard band is set to between the downlink CC DC64 and theextension band EB65.

FIG. 15B is an explanatory diagram illustrating a second setting exampleof the extension band set by the communication control unit 140. Thesetting pattern in the second setting example is the both-side symmetricsetting. In the second setting example, the usable frequency band is 704MHz-716 MHz and 734 MHz-746 MHz. For example, the communication controlunit 140 sets a downlink CC DC73 having the basic bandwidth of 10 MHz toa band of 735.5 MHz-744.5 MHz, and sets an uplink CC UC77 having thesame basic bandwidth of 10 MHz to a band of 705.5 MHz-714.5 MHz. Notethat, when the basic bandwidth is 10 MHz, since channel gaps areprovided on both ends of the component carrier, an effective bandwidthis 9 MHz, and the bandwidth includes 50 resource blocks in the frequencydirection.

In the second setting example, the communication control unit 140 setsan extension band EB71 to be added to the downlink CC DC73, to theexcess frequency band on the lower side of the downlink CC DC73. Theextension band EB71 has an extension bandwidth of 0.72 MHz (734.42MHz-735.14 MHz), and includes 4 resource blocks in the frequencydirection. A guard band GB72 having a bandwidth of 2 resource blocks isset to between the extension band EB71 and the downlink CC DC73.Further, the communication control unit 140 sets an extension band EB75to be added to the downlink CC DC73 to the excess frequency band on theupper side of the downlink CC DC73. The extension band EB75 has anextension bandwidth of 0.72 MHz (744.86 MHz-745.58 MHz), and includes 4resource blocks in the frequency direction. A guard band GB74 having abandwidth of 2 resource blocks is set to between the downlink CC DC73and the extension band EB75. Further, the communication control unit 140sets an extension band EB76 to be added to the uplink CC UC77 to theexcess frequency band on the lower side of the uplink CC UC77. Theextension band EB76 has an extension bandwidth of 1.08 MHz (704.42MHz-705.5 MHz), and includes 6 resource blocks in the frequencydirection. No guard band is set to between the extension band EB76 andthe uplink CC UC77. Further, the communication control unit 140 sets anextension band EB78 to be added to the uplink CC UC77 to the excessfrequency band on the upper side of the uplink CC UC77. The extensionband EB78 has an extension bandwidth of 1.08 MHz (714.5 MHz-715.58 MHz),and includes 6 resource blocks in the frequency direction. No guard bandis set to between the uplink CC UC77 and the extension band EB78.

FIG. 15C is an explanatory diagram illustrating a third setting exampleof the extension band set by the communication control unit 140. Thesetting pattern in the third setting example is the both-side asymmetricsetting. In the third setting example, the usable frequency band is 704MHz-716 MHz and 734 MHz-746 MHz. For example, the communication controlunit 140 sets a downlink CC DC83 having the basic bandwidth of 10 MHz toa band of 735.3 MHz-744.3 MHz, and sets an uplink CC UC87 having thesame basic bandwidth of 10 MHz to a band of 705.3 MHz-714.3 MHz. Notethat, when the basic bandwidth is 10 MHz, since channel gaps areprovided on both ends of the component carrier, an effective bandwidthis 9 MHz, and the bandwidth includes 50 resource blocks in the frequencydirection.

In the third setting example, the communication control unit 140 sets anextension band EB81 to be added to the downlink CC DC83, to the excessfrequency band on the lower side of the downlink CC DC83. The extensionband EB81 has an extension bandwidth of 0.36 MHz (734.58 MHz-734.94MHz), and includes 2 resource blocks in the frequency direction. A guardband GB82 having a bandwidth of 2 resource blocks is set to between theextension band EB81 and the downlink CC DC83. Further, the communicationcontrol unit 140 sets an extension band EB85 to be added to the downlinkCC DC83 to the excess frequency band on the upper side of the downlinkCC DC83. The extension band EB85 has an extension bandwidth of 0.72 MHz(744.66 MHz-745.38 MHz), and includes 4 resource blocks in the frequencydirection. A guard band GB84 having a bandwidth of 2 resource blocks isset to between the downlink CC DC83 and the extension band EB85.Further, the communication control unit 140 sets an extension band EB86to be added to the uplink CC UC87 to the excess frequency band on thelower side of the uplink CC UC87. The extension band EB86 has anextension bandwidth of 0.72 MHz (704.58 MHz-705.3 MHz), and includes 4resource blocks in the frequency direction. No guard band is set tobetween the extension band EB86 and the uplink CC UC87. Further, thecommunication control unit 140 sets an extension band EB88 to be addedto the uplink CC UC87 to the excess frequency band on the upper side ofthe uplink CC UC87. The extension band EB88 has an extension bandwidthof 1.08 MHz (714.3 MHz-715.38 MHz), and includes 6 resource blocks inthe frequency direction. No guard band is set to between the uplink CCUC87 and the extension band EB88.

Note that the settings of the extension band shown in FIG. 15A to FIG.15C are merely examples for description. For example, the communicationcontrol unit 140 may set the bandwidth of the component carrier, theextension band and the guard band to values different from the examplesdescribed above. Further, the communication control unit 140 may set thecomponent carrier, the extension band and the guard band whose numbersare different from the examples described above. Further, thecommunication control unit 140, as described using FIG. 12, may set thecomponent carrier and the extension band so that the positionalrelationship between the component carrier and the extension band in thefrequency direction is that they are overlapped with each other, or theyare reversed between the adjacent cells.

The terminal apparatuses communicating with the base station 100includes the non-legacy terminals supporting radio communication on theextension band (a first group of terminal apparatuses), and the legacyterminals not supporting radio communication on the extension band (asecond group of terminal apparatuses). The communication control unit140 generates the resource assignment information for the legacyterminal not depending on whether or not the extension band is set, andwhich of the setting patterns is selected when the extension band isset, and allows the radio communication unit 110 to transmit thegenerated resource assignment information. The resource assignmentinformation may include the channel arrangement information indicatingthe arrangement of the control channels such as the PRACH. Further, theresource assignment information may include the scheduling informationindicating the resource blocks to be assigned to each terminal apparatusfor data transmission. In the resource assignment information, theindividual resource blocks are identified by using the resource blocknumbers uniquely granted to the respective resource blocks through thecomponent carrier and the extension band. Then, the resource blocknumbers smaller than those of the resource blocks included in theextension band are granted to the resource blocks included in thecomponent carrier. Accordingly, the risk that the legacy terminalmisunderstands the meaning of the resource block numbers is solved tosecure backward compatibility of the resource assignment information.

The communication control unit 140 may generate the resource assignmentinformation for the non-legacy terminal, separately from the resourceassignment information for the legacy terminal. For example, the PRACHfor the non-legacy terminal may be arranged separately from the PRACHfor the legacy terminal. In this case, the communication control unit140 may allow the radio communication unit 110 to transmit the PRACHarrangement information for the non-legacy terminal, separately from thePRACH arrangement information for the legacy terminal, conveyed by theSIB2. This makes it possible to assign the PRACH for the non-legacyterminal to the extension band, and to assign more continuous resourceblocks to the legacy terminal on the PUSCH.

Furthermore, the communication control unit 140 may preferentiallyassign transmission of the uplink control signal (for example, theACK/NACK to downlink transmission, and a channel quality indicator(CQI)) of the non-legacy terminal to the extension band. Also in thiscase, since a rate of the resources used by the non-legacy terminalamong the resources of the uplink CC is reduced, it is possible toassign more continuous resource blocks to the legacy terminal on thePUSCH.

Furthermore, the communication control unit 140 may generate thescheduling information for the non-legacy terminal in a format differentfrom that of the scheduling information for the legacy terminal. As anexample, the scheduling information for the non-legacy terminal isdesigned so as to handle a start number exceeding the number of theresource blocks included in the component carrier, and the number of theblocks exceeding the number of the resource blocks. As another example,the scheduling information for the non-legacy terminal is designed so asto handle the bitmap up to the resource block number larger than thescheduling information transmitted to the legacy terminal. This makes itpossible to integrate the scheduling information on the componentcarrier and the scheduling information on the extension band into agroup of information.

Furthermore, the communication control unit 140 may assign downlinktransmission on the extension band for the non-legacy terminal closer tothe center of the cell, and may assign downlink transmission on thedownlink CC for the legacy terminal, and the non-legacy terminal closerto the cell edge. This can prevent large transmission power from beingused on the extension band in the downlink to suppress noise orinterference generated in the legacy terminal caused by the downlinksignal transmitted on the extension band.

<4. Configuration Example of Terminal Apparatus>

In this section, an example of a configuration of a terminal apparatus200 according to an embodiment will be described. The terminal apparatus200 may be any type of a radio communication terminal, for example, asmartphone, a personal computer (PC), a personal digital assistants(PDA), a portable navigation device (PND) or a game terminal. Theterminal apparatus 200 is the non-legacy terminal that supports radiocommunication on the extension band.

FIG. 16 is a block diagram illustrating an example of the configurationof the terminal apparatus 200. With reference to FIG. 16, the terminalapparatus 200 includes a radio communication unit 210, a storage unit220, and a control unit 230.

(1) Radio Communication Unit

The radio communication unit 210 is a radio communication interface (ora radio transmitter-receiver) that executes radio communication betweenitself and the base station 100. The radio communication unit 210transmits a radio signal to the base station 100 and receives a radiosignal from the base station 100, on the component carrier CC having thebasic bandwidth. Further, the radio communication unit 210 transmits theradio signal to the base station 100 and receives the radio signal fromthe base station 100, on the extension band according to control by acommunication control unit 234 to be described later. For example, theradio communication unit 210 establishes synchronization with thedownlink CC by detecting the primary synchronization signal and thesecondary synchronization signal transmitted from the base station 100.When the extension band is set by the base station 100, frame timing ofthe extension band is synchronized with frame timing of the componentcarrier. Therefore, in this case, the radio communication unit 210 canalso establish synchronization with the extension band as well as thedownlink CC.

The radio communication unit 210 receives the broadcast informationtransmitted on the PBCH of the downlink CC. The broadcast informationmay include, for example, the bandwidth information indicating the basicbandwidth of the component carrier. The radio communication unit 210further receives the BF setting information indicating the settingrelated to the extension band. For example, the radio communication unit210 may receive the BF setting information in the MIB on the PBCH, inthe SIB on the PDSCH, or in the individual signaling on the PDCCH.Parameters of the radio communication unit 210 depending on the band areset according to some indexes included in the BF setting information.

FIG. 17 is a block diagram illustrating an example of the detailedconfiguration of the radio communication unit 210 shown in FIG. 16. Withreference to FIG. 17, the radio communication unit 210 has a front end211, an orthogonal demodulation unit 212, a reception baseband unit 213,a transmission baseband unit 214, and an orthogonal modulation unit 215.

The front end 211 includes one or more transmission/reception antennas(ANTs); a filter (FIL); an amplifier (AMP) and a band-pass filter (BPF)in a reception branch; and a valuable gain amplifier (VGA), a band-passfilter (BPF), an amplifier (AMP), and an isolator (ISO) in atransmission branch.

The orthogonal demodulation unit 212 decomposes a reception signalinputted from the front end 211 into an I component and a Q component bya frequency adjusted by a frequency synthesizer, and filters the Icomponent and the Q component by a low-pass filter (LPF). The low-passfilter removes out-of-band noise, and aliasing noise that may begenerated by AD conversion.

The reception baseband unit 213 includes an analog-digital converter(A/D), a serial-parallel converter (S/P), a discrete Fourier transformer(DFT), a parallel-serial converter (P/S), and a demapper. Theanalog-digital converter converts a received analog signal into adigital signal at a sampling rate corresponding to a reception band. Thediscrete Fourier transformer converts a digital signal in a frequencydomain for each subcarrier, inputted from the serial-parallel converter,into a digital signal in a time domain.

The transmission baseband unit 214 includes a mapper, a serial-parallelconverter (S/P), an inverse discrete Fourier transformer (iDFT), aparallel-serial converter (P/S), and a digital-analog converter (D/A).The inverse discrete Fourier transformer converts a digital signal in atime domain for each subcarrier, inputted from the serial-parallelconverter, into a digital signal in a frequency domain. Thedigital-analog converter converts a digital signal into a transmissionanalog signal at a sampling rate corresponding to a transmission band.

The orthogonal modulation unit 215 filters an I component and a Qcomponent of the transmission analog signal inputted from thetransmission baseband unit 214 by a low-pass filter (LPF), and modulatesthe filtered signal into a transmission signal having a radio frequencyby a frequency adjusted by the frequency synthesizer. The transmissionsignal generated by the orthogonal modulation unit 215 is then outputtedto the front end 211.

For example, the cut-off frequency of the low-pass filter exemplified inFIG. 17, the sampling rate of the A/D conversion and the D/A conversion,and the FFT size of the DFT and the inverse DFT are circuit parametersto be adjusted depending on the transmission/reception band (and thebandwidth thereof). These circuit parameters may be set according to aband setting signal generated by the communication control unit 234 tobe described later on the basis of the indexes included in the BFsetting information. As a result, the radio communication unit 210 cantransmit and receive a radio signal on the extension band.

(2) Storage Unit

The storage unit 220 stores a program and data for operating theterminal apparatus 200 by using a storage medium such as a hard disk ora semiconductor memory. The data stored by the storage unit 220 mayinclude, for example, the bandwidth information indicating the basicbandwidth, and the BF setting information.

(3) Control Unit

The control unit 230 controls the whole operation of the terminalapparatus 200 by using a processor such as a CPU or a DSP. In anembodiment according to the present disclosure, the control unit 230 hasan application unit 232, and the communication control unit 234.

The application unit 232 mounts an application in an upper layerthereon. The application unit 232 generates data traffic to betransmitted to another apparatus, and outputs the generated data trafficto the radio communication unit 210. Further, the application unit 232processes the data traffic received by the radio communication unit 210from another apparatus.

The communication control unit 234 controls radio communication executedby the radio communication unit 210 according to a control signalreceived from the base station 100. The radio communication between theterminal apparatus 200 and the base station 100 is typically controlledin the resource block unit. For example, the communication control unit234 sets the circuit parameters of the radio communication unit 210depending on the band so as to be fitted to the basic bandwidthindicated by the broadcast information received by the radiocommunication unit 210. This allows the radio communication unit 210 totransmit and receive a radio signal on the component carrier.

Furthermore, the communication control unit 234, when the extension bandis set to the excess frequency band by the base station 100, resets(adjusts) the circuit parameters of the radio communication unit 210depending on the band so as to be fitted to the extension bandwidthindicated by the BF setting information received by the radiocommunication unit 210. This allows the radio communication unit 210 totransmit and receive a radio signal on the extension band in addition tothe component carrier. Since the extension band is set so as to have theextension bandwidth of the integer multiple of the size of the resourceblock, the BF setting information received by the radio communicationunit 210 can express the extension bandwidth with a small number of bitson the basis of the number of the resource blocks corresponding to theextension band width. The BF setting information may include an indexindicating whether the extension band is set on the upper side or thelower side of the component carrier.

Furthermore, the communication control unit 234 allows the radiocommunication unit 210 to execute radio communication according to theresource assignment information received by the radio communication unit210. The resource assignment information may include the channelarrangement information indicating the arrangement of the controlchannels such as the PRACH. For example, the radio communication unit210 is connected to the base station 100 by transmitting the randomaccess signal to the base station 100 on the PRACH for the legacyterminal indicated by the channel assignment information. The PRACH forthe non-legacy terminal, unlike the PRACH for the legacy terminalreported in the SIB2, may be assigned to the resource blocks in theextension band. Further, the radio communication unit 210 may transmitthe uplink control signals such as the ACK/NACK to downlinktransmission, and the CQI to the base station 100 on the PUCCH indicatedby the channel assignment information.

Furthermore, the resource assignment information may include thescheduling information indicating the resource blocks assigned to theterminal apparatus 200 for data transmission. For example, the radiocommunication unit 210 receives the downlink signal or transmits theuplink signal in the resource blocks indicated by the schedulinginformation.

When the extension band is set, the resource assignment informationdescribed above is generated based on the resource block numbersuniquely granted to the respective resource blocks through the componentcarrier and the extension band. The resource block numbers smaller thanthose of the resource blocks included in the extension band are grantedto the resource blocks included in the component carrier. Therefore, aformat of the resource assignment information received by the terminalapparatus 200 as the non-legacy terminal may be different depending onwhether or not the extension band is set. For example, when theextension band is not set, the maximum value of the resource blocknumbers that may be identified by the resource assignment informationcorresponds to the number of the resource blocks of the componentcarrier. In contrast, when the extension band is set, the maximum valueof the resource block numbers that may be identified by the resourceassignment information corresponds to the sum of the number of theresource blocks of the component carrier and the number of the resourceblocks of the extension band (that may include the guard band). Further,the size of the scheduling information expressed in a bitmap format whenthe extension band is set, becomes large than the size when theextension band is not set. The communication control unit 234 interpretsthese pieces of resource assignment information according to the settingof the extension band, and controls radio communication executed by theradio communication unit 210.

Note that a format of the resource assignment information received bythe legacy terminal is not changed depending whether or not theextension band is set, as a result of the adoption of the new numberingrule described above. The legacy terminal includes a radio communicationinterface having a configuration similar to that of the radiocommunication unit 210 of the terminal apparatus 200 described usingFIG. 17. However, it is enough for circuit parameters, such as thecut-off frequency of the low-pass filter, the sampling rate of the A/Dconversion and the D/A conversion, and the FFT size of the DFT and theinverse DFT of the radio communication interface of the legacy terminal,to be adjustable so as to be adapted to the 6 basic bandwidths. Thecontrol unit of the legacy terminal may ignore the setting informationand the resource assignment information on the extension band,transmitted from the base station 100.

<5. Flow of Processing>

In this section, a flow of processing in a radio communication systemincluding the base station 100 and the terminal apparatus 200 will bedescribed using FIG. 18 to FIG. 20.

[5-1. Band Setting Processing]

FIG. 18 is a flow chart illustrating an example of a flow of bandsetting processing executed by the base station 100.

With reference to FIG. 18, first, the communication control unit 140 ofthe base station 100 sets the one or more component carriers in theusable frequency band (Step S1). Next, the communication control unit140 determines whether or not the excess frequency band exists (StepS2). When the excess frequency band exists, the processing proceeds toStep S3. When the excess frequency band does not exist, the processingproceeds to Step S8.

At Step S3, the communication control unit 140 sets the extension bandhaving the extension bandwidth of the integer multiple of the RB size tothe excess frequency band (Step S3). The extension band set here isadded to the component carrier to extend the basic bandwidth of thecomponent carrier. Next, the communication control unit 140 sets theband adjacent to the downlink CC to the guard band (Step S4). The guardband may be handled as a part of the extension band. Next, thecommunication control unit 140 grants the unique resource block numbersto the resource blocks in the component carrier and the extension bandadded to the component carrier according to the new numbering rule (StepS5). Next, the communication control unit 140 determines the arrangementof some channels (Step S6). For example, the synchronization resourceand the broadcast channel are arranged in the resource blocks in thecenter of the downlink CC. The PRACH for the legacy terminal is arrangedin a part of the PUSCH of the uplink CC. The PRACH for the non-legacyterminal is arranged in the extension band in the uplink. Next, thecommunication control unit 140 generates the BF setting informationincluding the index indicating the setting of the extension band (StepS7).

At Step S8, the communication control unit 140 generates the channelarrangement information for the legacy terminal (Step S8). The channelarrangement information for the legacy terminal may indicate thearrangement of the PRACH (and other control channels) for the legacyterminal. In the channel arrangement information for the legacyterminal, the resource block numbers identifying the individual resourceblocks are not changed depending on whether or not the extension band isset.

The band setting processing described here may be executed when the basestation 100 initializes the operation of the cell, or may be executedduring the operation (for example, periodically) in order to dynamicallyupdate the setting of the extension band.

[5-2. Communication Control Processing]

FIG. 19A and FIG. 19B are a sequence diagram illustrating an example ofa flow of communication control processing according to an embodiment.

With reference to FIG. 19A, first, the base station 100 sets the one ormore component carriers and the one or more extension bands to theusable frequency band by executing the band setting processing describedusing FIG. 18 (Step S10).

Next, the base station 100 transmits the primary synchronization signaland the secondary synchronization signal on the synchronization resourcearranged in the resource blocks in the center of the downlink CC (StepS11). The terminal apparatus 200 as the non-legacy terminal establishessynchronization with the base station 100 by receiving suchsynchronization signals (Step S13).

Next, the base station 100 transmits the broadcast information includingthe bandwidth information indicating the basic bandwidth on thebroadcast channel of the downlink CC (Step S15). The communicationcontrol unit 234 of the terminal apparatus 200 sets the circuitparameters of the radio communication unit 210 depending on the band soas to be fitted to the basic bandwidth indicated by the receivedbroadcast information (Step S17). Note that the legacy terminal alsoreceives these synchronization signals and the broadcast informationfrom the base station 100. The channel arrangement information for thelegacy terminal may be broadcasted in the MIB or the SIB.

When the circuit parameters of the radio communication unit 210 are setso as to be fitted to the basic bandwidth in the terminal apparatus 200,it is possible to transmit and receive the radio signal on the componentcarrier. Next, the terminal apparatus 200 transmits a connection requestto the base station 100 on the uplink CC (Step S19). The base station100 transmits connection grant to the terminal apparatus 200 in responseto the connection request from the terminal apparatus 200 (Step S21).

Next, the base station 100 transmits an inquiry signal for inquiringcapability of the terminal apparatus 200 to the terminal apparatus 200on the downlink CC (Step S23). The terminal apparatus 200 transmits acapability response to the base station 100 in response to the inquirysignal from the base station 100 (Step S25). The capability responsetransmitted here includes capability information indicating that theterminal apparatus 200 is the non-legacy terminal, that is, it supportsradio communication on the extension band.

Next, the base station 100 transmits the BF setting informationincluding the index indicating the setting of the extension band to theterminal apparatus 200 (Step S27). The communication control unit 234 ofthe terminal apparatus 200 adjusts the circuit parameters of the radiocommunication unit 210 depending on the band so as to be fitted to theextension bandwidth (or the sum of the basic bandwidth and the extensionbandwidth) indicated by the received BF setting information (Step S29).The terminal apparatus 200 then transmits a BF setting completion reportto the base station 100 (Step S31).

After that, the sequence moves to FIG. 19B. When the downlink dataaddressed to the non-legacy terminal occurs (Step S33), the base station100 assigns the downlink transmission to the non-legacy terminal to theresource blocks in the downlink CC or the extension band added to thedownlink CC (Step S35). On the other hand, when the downlink dataaddressed to the legacy terminal occurs, the base station 100 assignsthe downlink transmission to the legacy terminal to the resource blocksin the downlink CC. Next, the base station 100 transmits the schedulinginformation indicating the downlink assignment, for example, on thePDCCH of the downlink CC (Step S37). The base station 100 then transmitsthe downlink data by using the assigned resource blocks (Step S39).

Furthermore, when the uplink data addressed to another apparatus occurs(Step S41), the terminal apparatus 200 as the non-legacy terminal, orthe legacy terminal transmits a scheduling request to the base station100 (Step S43). The base station 100 assigns the uplink transmission tothe resource blocks in the uplink CC or the extension band added to theuplink CC in response to the reception of the scheduling request (StepS45). The uplink transmission from the legacy terminal is assigned tothe resource blocks in the resource blocks in the uplink CC. Next, thebase station 100 transmits the scheduling information indicating theuplink grant to the terminal apparatus 200, for example, on the PDCCH ofthe downlink CC (Step S47). The terminal apparatus that has received thescheduling information then transmits the uplink data to the basestation 100 by using the assigned resource blocks (Step S49).

Note that there has been described here the example that, after the basestation 100 has confirmed the capability of the terminal apparatus 200,the base station 100 transmits the BF setting information to theterminal apparatus 200. However, the base station 100 may broadcast theBF setting information into the cell before confirming the capability ofthe terminal apparatus 200.

[5-3. Scheduling Processing]

FIG. 20 is a flow chart illustrating an example of a flow of schedulingprocessing according to an embodiment.

With reference to FIG. 20, first, the communication control unit 140 ofthe base station 100 recognizes the necessity of the scheduling (StepS61). For example, the communication control unit 140 may recognize thenecessity of the scheduling by recognizing that the downlink dataaddressed to a certain terminal apparatus has been delivered, or byreceiving the scheduling request for the uplink data from the terminalapparatus.

The communication control unit 140 that has recognized the necessity ofthe scheduling for a certain terminal, determines the capability of theterminal apparatus (Step S62). The capability information of eachterminal apparatus may be acquired in advance through the response tothe capability inquiry, and may be stored by the storage 130 of the basestation 100.

When the terminal apparatus is the non-legacy terminal, thecommunication control unit 140 further determines the position of thenon-legacy terminal (Step S64). For example, the position of theterminal may be measured using a GPS signal in the terminal and reportedto the base station 100, or may be measured in the base station 100.

The communication control unit 140, when the determined position isclose to the center of the cell (for example, the distance from the basestation 100 is below a predetermined value), assigns the resource blocksin the extension band to the non-legacy terminal (Step S66). On theother hand, the communication control unit 140, when the determinedposition is close to the cell edge, assigns the resource blocks in thecomponent carrier to the non-legacy terminal (Step S67). Note that, forthe uplink, Step S64 and Step S65 may be omitted. In this case, theuplink transmission of the non-legacy terminal is assignedpreferentially to the resource blocks in the extension band.

Furthermore, when the terminal apparatus is the legacy terminal, thecommunication control unit 140 assigns the resource blocks in thecomponent carrier to the legacy terminal (Step S67).

The communication control unit 140 then generates the schedulinginformation indicating the result of the scheduling, and allows theradio communication unit 110 to transmit the generated schedulinginformation (Step S68). The scheduling information for the legacyterminal is not changed depending on whether or not the extension bandis set. For example, the resource block numbers identifying the resourceblocks set in the component carrier are not dependent on the setting ofthe extension band. On the other hand, a format of the schedulinginformation for the non-legacy terminal (for example, the maximumresource block number that can be identified) may be changed dependingon whether or not the extension band is set.

Note that the flow of the processing described using FIG. 18 to FIG. 20is merely an example. The order of the processing steps may be changed,and the processing steps may be partially omitted, or an additionalprocessing step may be introduced.

<6. Summary>

Up to here, the embodiments of the technology according to thedisclosure have been described in detail. According to the embodimentsdescribed above, in a situation in which radio communication isperformed by the legacy terminal and the non-legacy terminal on thecomponent carrier having the basic bandwidth, and radio communication isperformed by the non-legacy terminal on the extension band set to theexcess frequency band, the resource assignment information that is notchanged depending on whether or not the extension band is set, istransmitted to the legacy terminal. Therefore, it is possible toeffectively utilize the frequency resources by using the band-fillingtechnology, while securing the compatibility of the operation for thelegacy terminal.

Furthermore, in a certain embodiment, radio communication on thecomponent carrier is controlled in the resource block (RB) unit, and thebandwidth of the extension band is set to the integer multiple of the RBsize. According to such a configuration, both of the resource blocks inthe component carrier and the resource blocks in the extension band canbe handled using the resource block numbers. Therefore, an excessivelycomplicated system is not required in order to control both of thelegacy terminal and the non-legacy terminal.

Furthermore, in a certain embodiment, the terminal apparatus is notifiedof the extension bandwidth by using the index based on the number of theresource blocks. According to such a configuration, since the terminalapparatus can be notified of the extension bandwidth with a small numberof bits, overhead of the control signal can be reduced.

Furthermore, in a certain embodiment, the resource block numbers areuniquely granted to the respective resource blocks through the componentcarrier and the extension band, and the numbers granted to the resourceblocks in the component carrier are smaller than the numbers granted tothe resource blocks in the extension band. Therefore, in the resourceassignment information such as the channel arrangement information orthe scheduling information, the resource block numbers of the resourceblocks included in the component carrier are not changed depending onwhether or not the extension band is set, and the bandwidth of theextension band. Therefore, it is possible to solve the risk that thelegacy terminal misunderstands the meaning of the resource blocknumbers.

Note that a series of control processing by each apparatus described inthis specification may be achieved by using any of software, hardware,and a combination of software and hardware. A program constitutingsoftware is stored in a storage medium (non-transitory media) inadvance, the medium being provided in the inside or outside of eachapparatus, for example. When each program is executed, for example, theprogram is read by random access memory (RAM) and executed by aprocessor such as a CPU.

The preferred embodiments of the present disclosure have been describedabove in detail with reference to the accompanying drawings, whilst thepresent disclosure is not limited to the above examples, of course. Aperson skilled in the art may find various alterations and modificationswithin the scope of the appended claims, and it should be understoodthat they will naturally come under the technical scope of the presentdisclosure.

Additionally, the present technology may also be configured as below.

(1)

A communication control apparatus including:

a communication control unit that controls radio communication performedby terminal apparatuses on a component carrier having a basic bandwidth,and sets at least one extension band to be added to the componentcarrier to at least a part of an excess frequency band,

wherein the terminal apparatuses include a first group of terminalapparatuses that support radio communication on the extension band, anda second group of terminal apparatuses that do not support the radiocommunication on the extension band, and

wherein the communication control unit transmits resource assignmentinformation that is not changed depending on whether or not theextension band is set, for the second group of terminal apparatuses.

(2)

The communication control apparatus according to (1),

wherein the communication control unit controls the radio communicationin a resource block unit, and sets a bandwidth of the extension band toan integer multiple of a size of a resource block.

(3)

The communication control apparatus according to (2),

wherein the resource assignment information is generated based onresource block numbers uniquely granted to the respective resourceblocks through the component carrier and the extension band, and

wherein the resource block numbers smaller than the resource blocknumbers of the resource blocks included in the extension band aregranted to the resource blocks included in the component carrier.

(4)

The communication control apparatus according to (2) or (3),

wherein the communication control unit uses an index based on the numberof the resource blocks corresponding to the bandwidth of the extensionband to notify the first group of terminal apparatuses of the setting ofthe extension band.

(5)

The communication control apparatus according to (3),

wherein the resource assignment information includes schedulinginformation indicating the resource blocks assigned to each terminalapparatus for data transmission.

(6)

The communication control apparatus according to (5),

wherein the scheduling information identifies the assigned resourceblocks by specifying a start number and the number of blocks of a set ofthe resource blocks, and

wherein the scheduling information for the first group of terminalapparatuses can identify the resource blocks included in the extensionband.

(7)

The communication control apparatus according to (5),

wherein the scheduling information identifies the resource blocksassigned in a bitmap format, and

wherein the scheduling information for the first group of terminalapparatuses includes a bitmap up to the resource block number largerthan the scheduling information for the second group of terminalapparatuses.

(8)

The communication control apparatus according to (3),

wherein the resource assignment information includes channel arrangementinformation indicating an arrangement of a control channel.

(9)

The communication control apparatus according to (8),

wherein the communication control unit assigns a first random accesschannel for the first group of terminal apparatuses to the resourceblocks in the extension band, and assigns a second random access channelfor the second group of terminal apparatuses to the resource blocks inthe component carrier, and

wherein the channel arrangement information for the second group ofterminal apparatuses indicates an arrangement of the second randomaccess channel.

(10)

The communication control apparatus according to (9),

wherein the communication control unit further transmits separatechannel arrangement information indicating an arrangement of the firstrandom access channel, for the first group of terminal apparatuses.

(11)

The communication control apparatus according to any one of (2) to (8),

wherein the radio communication is performed by a frequency divisionduplex (FDD) scheme, and

wherein the communication control unit sets a guard band on which aradio signal is not transmitted, to between the component carrier andthe extension band, in a downlink.

(12)

The communication control apparatus according to (11),

wherein the guard band has a bandwidth of an integer multiple of a sizeof the resource block.

(13)

The communication control apparatus according to (12),

wherein the terminal apparatuses are not explicitly notified of thesetting of the guard band, and

wherein the communication control unit prevents transmission of adownlink signal on the guard band.

(14)

The communication control apparatus according to any one of (1) to (13),

wherein the communication control unit assigns a resource on which asynchronization signal for synchronizing the terminal apparatus withboth of the component carrier and the extension band is transmitted, toa resource block in a center of the component carrier, and

wherein the communication control unit sets the component carrier andthe extension band in a manner that an arrangement of the resource isshifted between cells overlapped with each other or adjacent to eachother.

(15)

A communication control method including:

controlling radio communication performed by terminal apparatuses on acomponent carrier having a basic bandwidth;

setting at least one extension band to be added to the component carrierto at least a part of an excess frequency band;

including a first group of terminal apparatuses that support radiocommunication on the extension band, and a second group of terminalapparatuses that do not support the radio communication on the extensionband, in the terminal apparatuses; and

transmitting resource assignment information that is not changeddepending on whether or not the extension band is set, for the secondgroup of terminal apparatuses.

(16)

A radio communication system including a communication control apparatusand a plurality of terminal apparatuses that execute radiocommunication,

wherein the communication control apparatus includes a communicationcontrol unit that sets a component carrier having a basic bandwidth andsets at least one extension band to be added to the component carrier toat least a part of an excess frequency band,

wherein the plurality of terminal apparatuses include a first group ofterminal apparatuses that support radio communication on the extensionband, and a second group of terminal apparatuses that do not support theradio communication on the extension band, and

wherein the communication control unit of the communication controlapparatus transmits resource assignment information that is not changeddepending on whether or not the extension band is set, for the secondgroup of terminal apparatuses.

(17)

A terminal apparatus including:

a radio communication unit that communicates with a communicationcontrol apparatus controlling radio communication performed on acomponent carrier having a basic bandwidth, the communication controlapparatus setting at least one extension band to be added to thecomponent carrier to at least a part of an excess frequency band; and

a control unit that allows the radio communication unit to execute theradio communication according to resource assignment informationreceived from the communication control apparatus in a format differentdepending on whether or not the extension band is set by thecommunication control apparatus.

(18)

The terminal apparatus according to (17),

wherein the resource assignment information includes schedulinginformation capable of specifying a different maximum value of aresource block number depending on whether or not the extension band isset.

(19)

The terminal apparatus according to (17),

wherein the resource assignment information includes schedulinginformation including a bit map having a different size depending onwhether or not the extension band is set.

(20)

The terminal apparatus according to (17),

wherein the resource assignment information includes channel arrangementinformation indicating an arrangement of a control channel.

REFERENCE SIGNS LIST

-   100 communication control apparatus (base station)-   110 radio communication unit-   140 communication control unit-   200 terminal apparatus (non-legacy terminal)-   210 radio communication unit-   234 communication control unit

1. A communication control apparatus comprising: a communication controlunit that controls radio communication performed by terminal apparatuseson a component carrier having a basic bandwidth, and sets at least oneextension band to be added to the component carrier to at least a partof an excess frequency band, wherein the terminal apparatuses include afirst group of terminal apparatuses that support radio communication onthe extension band, and a second group of terminal apparatuses that donot support the radio communication on the extension band, and whereinthe communication control unit transmits resource assignment informationthat is not changed depending on whether or not the extension band isset, for the second group of terminal apparatuses.
 2. The communicationcontrol apparatus according to claim 1, wherein the communicationcontrol unit controls the radio communication in a resource block unit,and sets a bandwidth of the extension band to an integer multiple of asize of a resource block.
 3. The communication control apparatusaccording to claim 2, wherein the resource assignment information isgenerated based on resource block numbers uniquely granted to therespective resource blocks through the component carrier and theextension band, and wherein the resource block numbers smaller than theresource block numbers of the resource blocks included in the extensionband are granted to the resource blocks included in the componentcarrier.
 4. The communication control apparatus according to claim 2,wherein the communication control unit uses an index based on the numberof the resource blocks corresponding to the bandwidth of the extensionband to notify the first group of terminal apparatuses of the setting ofthe extension band.
 5. The communication control apparatus according toclaim 3, wherein the resource assignment information includes schedulinginformation indicating the resource blocks assigned to each terminalapparatus for data transmission.
 6. The communication control apparatusaccording to claim 5, wherein the scheduling information identifies theassigned resource blocks by specifying a start number and the number ofblocks of a set of the resource blocks, and wherein the schedulinginformation for the first group of terminal apparatuses can identify theresource blocks included in the extension band.
 7. The communicationcontrol apparatus according to claim 5, wherein the schedulinginformation identifies the resource blocks assigned in a bitmap format,and wherein the scheduling information for the first group of terminalapparatuses includes a bitmap up to the resource block number largerthan the scheduling information for the second group of terminalapparatuses.
 8. The communication control apparatus according to claim3, wherein the resource assignment information includes channelarrangement information indicating an arrangement of a control channel.9. The communication control apparatus according to claim 8, wherein thecommunication control unit assigns a first random access channel for thefirst group of terminal apparatuses to the resource blocks in theextension band, and assigns a second random access channel for thesecond group of terminal apparatuses to the resource blocks in thecomponent carrier, and wherein the channel arrangement information forthe second group of terminal apparatuses indicates an arrangement of thesecond random access channel.
 10. The communication control apparatusaccording to claim 9, wherein the communication control unit furthertransmits separate channel arrangement information indicating anarrangement of the first random access channel, for the first group ofterminal apparatuses.
 11. The communication control apparatus accordingto claim 2, wherein the radio communication is performed by a frequencydivision duplex (FDD) scheme, and wherein the communication control unitsets a guard band on which a radio signal is not transmitted, to betweenthe component carrier and the extension band, in a downlink.
 12. Thecommunication control apparatus according to claim 11, wherein the guardband has a bandwidth of an integer multiple of a size of the resourceblock.
 13. The communication control apparatus according to claim 12,wherein the terminal apparatuses are not explicitly notified of thesetting of the guard band, and wherein the communication control unitprevents transmission of a downlink signal on the guard band.
 14. Thecommunication control apparatus according to claim 1, wherein thecommunication control unit assigns a resource on which a synchronizationsignal for synchronizing the terminal apparatus with both of thecomponent carrier and the extension band is transmitted, to a resourceblock in a center of the component carrier, and wherein thecommunication control unit sets the component carrier and the extensionband in a manner that an arrangement of the resource is shifted betweencells overlapped with each other or adjacent to each other.
 15. Acommunication control method comprising: controlling radio communicationperformed by terminal apparatuses on a component carrier having a basicbandwidth; setting at least one extension band to be added to thecomponent carrier to at least a part of an excess frequency band;including a first group of terminal apparatuses that support radiocommunication on the extension band, and a second group of terminalapparatuses that do not support the radio communication on the extensionband, in the terminal apparatuses; and transmitting resource assignmentinformation that is not changed depending on whether or not theextension band is set, for the second group of terminal apparatuses. 16.A radio communication system comprising a communication controlapparatus and a plurality of terminal apparatuses that execute radiocommunication, wherein the communication control apparatus includes acommunication control unit that sets a component carrier having a basicbandwidth and sets at least one extension band to be added to thecomponent carrier to at least a part of an excess frequency band,wherein the plurality of terminal apparatuses include a first group ofterminal apparatuses that support radio communication on the extensionband, and a second group of terminal apparatuses that do not support theradio communication on the extension band, and wherein the communicationcontrol unit of the communication control apparatus transmits resourceassignment information that is not changed depending on whether or notthe extension band is set, for the second group of terminal apparatuses.17. A terminal apparatus comprising: a radio communication unit thatcommunicates with a communication control apparatus controlling radiocommunication performed on a component carrier having a basic bandwidth,the communication control apparatus setting at least one extension bandto be added to the component carrier to at least a part of an excessfrequency band; and a control unit that allows the radio communicationunit to execute the radio communication according to resource assignmentinformation received from the communication control apparatus in aformat different depending on whether or not the extension band is setby the communication control apparatus.
 18. The terminal apparatusaccording to claim 17, wherein the resource assignment informationincludes scheduling information capable of specifying a differentmaximum value of a resource block number depending on whether or not theextension band is set.
 19. The terminal apparatus according to claim 17,wherein the resource assignment information includes schedulinginformation including a bit map having a different size depending onwhether or not the extension band is set.
 20. The terminal apparatusaccording to claim 17, wherein the resource assignment informationincludes channel arrangement information indicating an arrangement of acontrol channel.